In the related art, any desired junction surface of a multi-junction semiconductor has been inspected as follows. The multi-junction semiconductor is irradiated with an ultrasound wave, and the junction surface is inspected, based on a reflected wave therefrom. For example, claim 1 in PTL 1 discloses an ultrasound inspection device which emits the ultrasound wave to a subject so as to inspect the junction surface inside the subject, based on a reflected wave signal thereof.